


Of Alchemy & Little Brothers

by NorthernWall



Category: Fullmetal Alchemist - All Media Types, Fullmetal Alchemist: Brotherhood & Manga
Genre: A very old somewhat strange idea, Body Swap, F/M, Immediately Post-Canon, Sibling Love, Somewhat crack-treated-seriously
Language: English
Status: Completed
Published: 2020-04-07
Updated: 2020-04-07
Packaged: 2021-03-01 17:59:50
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,433
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23521189
Author URL: https://archiveofourown.org/users/NorthernWall/pseuds/NorthernWall
Summary: Father's been defeated and the entire country has just narrowly dodged becoming a philosopher's stone. All around, a win for the forces of good. There's just one problem.“We have a small problem.” She faces the hodge-podge group. “Our souls went back wrong.” Blank faces stare back at her.“It’s true.” Her voice resonates, but the speech pattern is all Alex. “My sister is trapped in my body, and I am in hers.”
Relationships: Alex Louis Armstrong & Olivier Mira Armstrong, Olivier Mira Armstrong/Miles
Comments: 10
Kudos: 51





	Of Alchemy & Little Brothers

**Author's Note:**

> Hello lovelies,
> 
> So. I wrote this some time ago and always loved it, but one person who read it said it was "too silly" to post and I felt self-conscious ever since. Well, I recently rediscovered it and I still love it, so here we are.
> 
> Happy reading!

Her first thought as her soul slams back into her body and she gasps that first breath of  _ life _ itself, is that for someone who was just  _ dead _ she feels fine. Honestly, she feels better than fine. Her hands hurt, yes, and her shoulder too, but her arm no longer feels broken, and when she breathes her fractured ribs no longer catch painfully. She blinks her eyes open and raises her arm, curious, it still feels fine. There’s only one problem, she realizes, as her arm swims into view; that is  _ not  _ her arm. She stares. She recognizes it immediately, the bloated muscles and metal gauntlets can only belong to one person; her brother. And, for the first time in many years, Olivier Mira Armstrong is frightened. 

She pushes herself into a sitting position and looks around. All around her, others are coming back to life, disoriented and unsure. Someone asks if she’s alright, but she ignores him and begins an almost frantic search. She has to find her body, has to know, is Alex’s soul in her body? Is anyone else a soul in a body that it doesn’t call home? She finds him. Her? Her body, at any rate, slumped against a wall. Her breath catches and a shiver runs down her spine.  _ Someone stands on your grave _ , a childhood theory on the sensation resurfaces abruptly. Shaking it away, she kneels over her own body. 

From her vantage point, she can see herself as Alex sees her. Terrifyingly small,  _ fragile _ . Honestly, it’s almost insulting. She shakes her (his?) shoulder. “Alex?” She whispers, knowing she’ll look insane if anyone sees  _ Alex  _ shaking his older sister and calling her by his own name. Blue eyes flutter open and relief floods her. 

“Wha-?” Alex, at least she really hopes it’s Alex, and she’s not going to have to run all around Central, maybe even all over Amestris, to figure out where his soul is, and where the body of the soul in her body is. “Who are you? Why do you look like me?” Alex demands. He moves to rise and stops with a groan of pain.

“Hush.” She claps a hand over his mouth, hers really, and it covers almost her whole face. She frowns, she had never thought of herself as  _ small _ before, even though she knows she is. “Alex, I am you. Well, no. It’s Olivier, in your body. You’re in mine. I think.” She hopes she doesn’t actually look that comically  _ cute _ when she is surprised. 

“But,” he splutters, and it doesn’t suit her stoic face at all, “that’s impossible.” 

“We just had our souls eaten and spit back out. Anything’s possible.” She counters. “We need to get out of here. Come on.” She slips massive hands under her shoulders and knees and lifts. Has she always been this light? She would never allow herself to be carried in this manner, but Alex, in her body, offers no protest. “Close your eyes.” She orders, sternly. 

“Why?” Obedient, but questioning, Alex complies.

“Because,” she brushes past soldiers, muttering quietly, “ _ I  _ only allow myself to be carried if I’m unconscious. So, shut it.” 

They make it back to the manor and she sends for the Armstrong family doctor. The Briggs men trickle in and she accosts them demanding answers about what has happened to her men. They are surprised by the fire in the Strongarm Alchemist’s eyes, but they answer her. She has lost many men.  _ So many men.  _ She cries, something she never does. Alex’s body makes it so, so easy though. For the first time, she wonders if Alex’s propensity to tears is, at least in part, physical rather than psychological. Thinking of her men hurts, too much, and she pushes past it to begin thinking of solutions. Alex is an alchemist, and when her body is strong enough, he will surely have an answer for her. 

Alex has no answer, though. Frantic, she sends men to the hospital to bring her the Fullmetal Alchemist. He refuses to come. She dons her uniform (Alex’s uniform, actually, she had absently grabbed her own jacket and ripped the sleeve) and heads to the hospital herself. 

“I’m sorry, Major.” Fullmetal tells her when she explains she has an urgent, confidential, need of his alchemical skills. “I gave up alchemy for Al’s body.” 

She turns to the younger Elric and begs,  _ begs _ , him for help. Humiliating, to be sure, but Alex would do it, and they don’t know, yet, that she isn’t him. 

“They won’t let me out of bed, Major.” He apologizes. “I can research, though, if you tell me what the problem is.” He is weak, but he is kind. He pities her, pities Alex, their despair. 

“I have volumes of alchemical knowledge at the manor.” She knows Alex keeps more books than he can ever use in the family library. “You can convalesce there, under the care of the Armstrong family physician.” 

The brothers exchange nervous looks. “What’s going on, Major?” Edward asks suspiciously. 

“I’ll explain at the manor.” She grits her teeth and clenches her fists. “I’ll pay you for your troubles, and it’ll free up this room for the civilians still being treated.” The brothers are studying her suspiciously, and she knows she isn’t acting enough like Alex. She is desperate, though. “Please?” 

“Okay.” Soft-hearted Alphonse agrees. “Ed and I will come research your problem, but we expect answers. And, anything or anyone, we need.” 

“Sure. Whatever.” She tries, but not that hard, to sound more like Alex. “I’ll arrange transport.” 

She should have expected this, she thinks, as the manor staff roll in not just Alphonse, in his wheelchair, but also Mustang, Havoc, and Hawkeye, confined to wheelchairs of their own. Ed hobbles in with Winry, followed by Izumi and Sig, and Catalina brings up the rear loaded down with bags of the assorted crew’s belongings. 

“This everyone?” She asks, irritated. The physician is going to be annoyed with her for expanding his patient load from three to seven. 

“Yup.” Alphonse smiles at her. He has had his hair cut and looks better already. She makes a mental note to have extra food brought up for him regularly, he is still skin and bones. “What’s going on?”

She sticks her head out the door and calls to have Alex brought in, not in those words. She stifles an angry snort when the physician rolls Alex in in a wheelchair. She can walk. But, Alex is taking excellent care of her body. Far better than she would have. 

“We have a small problem.” She faces the hodge-podge group. “Our souls went back wrong.” Blank faces stare back at her. 

“It’s true.” Her voice resonates, but the speech pattern is all Alex. “My sister is trapped in my body, and I am in hers.” 

Mustang bursts out laughing. “Are you actually trying to tell me, that little Oli is now Alex and vice-versa?” 

She shouldn’t, but she slaps Mustang. Alex’s hand is larger and more forceful than her own and the blind man topples out of his wheelchair. The room bursts into angry protests. 

Mustang pulls himself up into his wheelchair, still laughing. “That’s Oli, alright. Alex would never do that.”

“Watch it, brat.” She warns, angrily. 

“Whatever you say.” He beams cheekily in her general direction. 

Once the group can stop laughing, they set to work. Winry and Catalina retrieve books, and Hawkeye reads quietly to Mustang. The alchemists bandy theories and discuss options. She leaves. Alchemy makes her head hurt, and she is worn out.

She makes her escape to the hedge maze in the back garden. She stretches out in the grassy center and watches the blue, blue sky. It makes her think of Buccaneer and she closes her eyes. She doesn’t remember getting sleepy, but she dozes. 

_ “Come back, sister!” She is running through the maze. Blond hair whips out of sight, ringing laughter echoing in the summer sun. This is real, she thinks, but not right. She stumbles, scrapes her knee. Tears flow loud and hard.  _

_ “Honestly, Alex. You’re such a baby.” A young Olivier is leaning over her, examining her knee. “It’s just a little scrape.” Her brain scrambles to right the image, she remembers vaguely leaning over Alex as a child, scoffing at his minor injury. This is wrong, this is not her memory.  _

_ “I am not.” Pouty lips scowl, arms cross even as tears trickle. A defiant sniffle.  _

_ “Ugh. Baby.” Olivier rises and leaves. She rises shakily and runs back to mother who will kiss the hurt knee, and later, scold Olivier for not looking after her brother.  _

She jerks awake. Alex’s memory is in her brain. Her heart is pounding, and she sits up. The back of her shirt is grass stained, but no matter, it’s Alex’s anyway. Rising, she returns to the house, to ask the alchemists why she can remember Alex’s memories. She needs to ask Alex, if he dreams her memories. If he does not, then, perhaps her soul is fading away. She realizes she is afraid. Mere hours ago, being stuck as her brother forever had been the worst possible outcome, and now she fears she will simply cease to exist.

The alchemists are puzzled, but they have new places to look when she tells them. Alex has gone up to her room, to rest. They tell her to ask him when he awakes. She sets off to wake him, and is stopped by the butler. 

“A Major Miles is here to see you, Miss.” The butler has been apprised of the situation, and has taken to the change readily, as though there is nothing in the world strange about reversed bodies. “I’ve told him to wait in the drawing room. He knows you are not to be disturbed.” They peek into the drawing room, and Miles is unsurprisingly, not there. The butler is flummoxed, but Olivier sets off for her childhood bedroom.

Miles, not yet informed of the situation, would have taken the butler’s directions the way they would have been meant under normal circumstances. No matter how strongly-worded, Miles will never heed a warning not to disturb Olivier. He cannot disturb her, truthfully. Distract her, yes, but she will always be glad to see him. Knowing she is wounded, and sleeping, will only make him more desperate to see her. Olivier nearly sprints to her old room, knowing that Miles will be kissing her sleeping forehead, twining his fingers in her hair, murmuring lovingly to her, and maybe even crawling gently onto the bed to embrace her. 

_ She  _ would wake and smile, a little. She would chide him for doting, kiss him back, and snuggle closer.  _ Alex  _ will panic. He will think the worst possible things, when Miles’ lips meet his and, really, Olivier can’t blame him for that. He doesn’t know, hasn’t been told, what Miles really means to her. What secrets they carry are theirs, not his. 

“Major! What is the meaning of this?” She is too late, and Alex’s startled yell echoes from her room. 

“Miles!” She throws open the door. Miles freezes, and looks from one to the other. He is poised to kiss her (Alex) and is bewildered by the rage and shock and disgust all over her face. 

“What’s going on?” He asks, looking at Alex who he thinks is Olivier. 

“That’s Alex.” She blurts. “ _ I’m _ Olivier.”

“What?” He straightens and steps back. He doesn’t approach her, though. “I don’t-”

“Our souls got switched.” She wants to throw her arms around him, to hold him and be held by him. 

“Oh.” He blinks, slowly, behind his goggles. He gives a thin smile. “You’ll forgive me if I don’t kiss you, then.” He sways in place. “Either of you.” His knees buckle and he crumples to the floor. Olivier thinks she should catch him, he, after all, would catch her, but she is offended by his weakness. She does, however, prop his feet up and wait for him to regain consciousness. 

“What did he mean, sister?” Alex asks, eyes narrowed, face hard. Olivier shudders, she can see now, how terrifying her face can be. No wonder men fear her.

“It’s nothing.” She touches Miles’ face gently, but pulls her hand back immediately. Alex’s fingers are too big, too rough, for the action. “Miles is-” She shakes her head. “You wouldn’t understand.”

“Try me.” Alex is still glaring at her, and she feels that maybe, he deserves to know. He is, after all, the one living in her body, perhaps forever if they can’t work this out. 

“We broke the law.” She admits, studying Miles’ face. His eyelids are starting to flicker, consciousness returns slowly. “Miles and I are married.” 

“You’re what?!” She really hopes she doesn’t look that stupid, ever. She hates seeing her own face like this. 

“Married, Alex.”

“When?”

“Seven years.” She grins a little at his shock. “Not long after the Ishval conflict.”

“Why?” Alex is staring. She frowns a little. She expected a little more happiness, and less shock. Alex always seemed inordinately fond of Miles. 

“Love.” She admits, with a shake of her head. “Call me silly, if you like, but I love Miles.”

Alex is beaming, suddenly. “Congratulations, Sister! You’re not going to die alone!” He moves as though to rise, but stops and clutches the fractured ribs with a wince. 

“I don’t think you’re silly.” Miles offers a weak smile from the floor. “Although, I think you look it just now- Ow!” Olivier smacks him and Alex’s big hands sting more than she intends. 

“Alex,” she remembers suddenly, “did you dream?” 

“What?” 

“Did you dream while you were sleeping?” 

“Yes.” Alex nods, slowly, and her long blond locks obscure her (his) face. “It was most odd.”

“Was it about me?” She asks. She is nervous, suddenly. There are many things she has seen and done that she doesn’t want him to see. 

“Yes. As a child. Did you-” he is figuring it out, “did you ever tell Mother you hated me for being a boy?”

“Yes.” Her heart pounds. “I’m sorry,” she offers, “I was jealous.” 

“I know.” Alex nods again, and then shakes the hair out of his face. “So, our memories are still, somehow, connected to our bodies?” 

“All of them?” Miles pushes himself into a sitting position and surveys the two siblings. “Awkward.” He gets another smack, softer this time.

“I think it’s just the ones that pertain to each other.” Alex offers, grimacing. “If there are things you remember that,” he pauses, “hurt you, I am sorry.”

“If we can get this taken care of soon, it won’t matter, anyway.” Olivier shrugs. She thinks Alex is soft to be worried about her. “You have memories that might hurt me?” She is curious, nonetheless. 

“I haven’t always been a good younger brother.” Alex sounds sincere. “I am sorry.” 

“I think I should go.” Miles stands. “You two should talk.” He moves as though to kiss Olivier but stops with a slight shudder. “Sorry, love.” 

He leaves, and then they are alone. Alex and Olivier study each other. She rises and pulls her old vanity chair to the edge of the bed. She had never really used it as a child, or any of the feminine  _ pink  _ things her mother had insisted on. She sits, and the chair creaks under Alex’s weight. 

“What do you mean?” She asks, at last. “How were you a bad little brother?” She can think of all the ways she was a horrible older sister. She was cold and cruel and  _ jealous. _ Alex was always warm and kind and  _ innocent.  _

“I used to tattle.” He offers with an apologetic shrug. He winces as he jolts her broken arm. “Even when I knew you were already in hot water. Even if I knew you wouldn’t get supper, or have to stay home from the park, or whatever.” 

“Oh.” It’s a small thing, but she wonders. “Were you the one who told Mother I gave Eloise Polikarpov a black eye?” The two girls had had an ugly fight way back in school. Honestly, she can’t remember why. She does, however, remember the aftermath.

“Yes.” He admits. “I’m sorry I got you in so much trouble.” He remembers the aftermath, too. “I was upset because you said I couldn’t come with you to get ice cream cones from that little cart on the far side of the park. Do you remember it?” 

“Yes.” She smiles slightly. “Best ice cream in Central. Worked for you, didn’t it? Your nanny took you, and I was grounded for a month.” 

“Do you remember when you lost your training sword and Master Richards said you were irresponsible, but then we found it hidden in the garden?” 

“Yes.” She frowns. “That was you? I blamed poor Strongine!” 

“You were so much better than me. I was jealous.” 

“You were a child!” She shakes her head. “I was already a teen. You were already so good at alchemy, anyway. I hardly thought you cared about fencing.” 

“I really wanted to do whatever you did.” Alex smiles sheepishly, and once again she is startled by an expression her face should not hold. “Alchemy was a consolation prize.” 

“You’re so good, though!” She stares. “You idiot!” 

“So.” Alex says, shaking his (her) head, too. “We’re a fine pair.” 

“Indeed.” She sits back, reaches up to run an absent hand through her hair. Her fingers brush Alex’s bare scalp and she cringes. “I’m going to see what they’ve resolved.” She leaves before he can say anything else. 

The alchemists are arguing. “It’s not human transmutation, if the souls are still here.” Edward says as she pushes open the door. 

“Do you really want to risk it?” Mustang shakes his finger at thin air. 

“I think Brother is right.” Alphonse offers. “But, we should see if the Armstrongs are game.” 

“Hello, Sir.” Lt. Hawkeye greets, halting the argument. “How are you feeling?”

“Like an idiot in this useless body.” Honestly, she feels fine. Her body is the weak one tucked into bed, and Alex’s is boldly marching around the house. She refuses to admit it, though. “What isn’t human transmutation?” 

“Perhaps we should explain when Alex is awake.” Izumi interjects, somehow fierce and motherly at the same time.

“He’s awake. I’ll send for him.” 

She doesn’t understand a word they are saying. She pretends her hatred of alchemy revolves arounds its principles, and it does, but also the fact it all sounds like Cretan to her. She gathers they think since their souls are in the same realm, they can switch them without opening the portal. She thinks this sounds fine, since the portal is what got them in trouble in the first place. She agrees. So does Alex. 

Miles helps Alex out of the wheelchair to sit on the floor. Hawkeye finds chalk. Under the careful eyes of two of the alchemists she begins to draw her half of the transmutation circle. She has no idea what they mean, when they tell her to harness the energy. Struggling, left-handed, Alex seems to understand but his lines are shaky. At last they finish.

“Remember,” Ed warns them. “If we’re wrong, you’re about to commit the great taboo. The cost is high.” They both nod, somberly.

Alex stops to ask about some technical details, and Olivier beckons Izumi close. “If this goes wrong, and I know there might not be anything you can do, but if you can, save him.” She thinks. “And don’t let anyone seal my soul to a chair, or anything.” Izumi nods, claps her on the back and steps back. 

Alex and Olivier step into the circle and look at each other. It’s odd, Olivier thinks, to be this tall. To see herself like this. Looking up at her, she knows Alex is thinking the same thing. They sit down and Alex presses his (her? she really wants this to be normal again) hands to the edge of the array. A bright white light pulses, filling the room. Olivier closes her (Alex’s) eyes and falls to the ground.

Pain. She is in pain. Her hands no longer hurt, and her shoulder no longer aches. But, oh, her broken arm throbs and as she gasps for air stabbing pain courses through her ribs. Her eyes open, slowly, and she lifts her unbroken arm. Slender arm, little hand. Hers. She turns her head, and Alex is sitting up, slowly, flexing his own arms. He smiles at her, and she smiles back. 

“Thank goodness,” she chuckles, “for little brothers.” 

**Author's Note:**

> Thanks for reading! 
> 
> Please drop me a note and let me know what you think. <3


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